JP2001310339A - Manufacturing method for phenolic resin foam-molding with skin layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a phenolic resin foam-molding with a skin layer, in which no poor external appearance due to foams develops, the design properties of which are favorable and in which no compounding of skin materials is necessary. SOLUTION: In order to manufacture the phenolic resin foam-molding with the skin layer, a silicone rubber mold 3 is installed with in a mold 1 having two openable and closable mold members 2a and 2b, an expansion curable phenolic resin compound liquid including at least a phenolic resin, a curing agent and a foaming agent is poured in a space part 4 after a curable resin composition containing a synthetic resin and the curing agent as a skin layer is coated on the silicone rubber mold 3 so as to foam-mold the compound liquid in the silicon rubber mold 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a foamed phenolic resin molded article used for industrial materials and building materials, and more particularly to a method for producing a foamed phenolic resin molded article having a skin layer in which poor appearance due to bubbles is improved. .

[0002]

2. Description of the Related Art Phenolic resin foams have excellent flame retardancy, heat resistance and soundproofing properties, and also have good chemical resistance and weather resistance. ,
It is being widely used as a building material and industrial material. As a building material, it is used as an interior material such as a wall material, a partition material, a door, a floor heat insulating material, and a ceiling panel.

When used as an interior material, a skin material such as a decorative plywood or a decorative sheet is generally compounded in order to impart a design property to the surface of the phenol resin foam.
Examples of the skin material include a metal sheet, an inorganic material, a synthetic resin sheet, a rubber sheet, and a plaster paper,
It is composited with the foamed molded article via an adhesive layer. Many skin materials are fire-treated or flame-retarded to impart functionality other than design.

However, when the phenolic resin foam has a complicated shape, it is difficult to bring the skin material into close contact with the foam material, and an extra space is created between the skin material and the foam material, and the original shape is not obtained. May be impaired. In particular, hard skin materials such as natural woods are difficult to process, and it is extremely difficult to attach them to a curved surface.

[0005] When a foamed phenolic resin article with a skin material is used at a high temperature such as in summer, condensed water and the like generated during the reaction from the foam are vaporized, and this water vapor accumulates at the boundary with the skin material. Therefore, there is a problem that deformation such as swelling or warping occurs with time.

[0006] Furthermore, the process of manufacturing the interior material requires at least three steps of manufacturing a skin material, manufacturing a phenolic resin foam, and bonding the skin material and the phenolic resin foam, resulting in poor industrial productivity.

In connection with the above problem, the present inventor disclosed in Japanese Patent Laid-Open No.
Japanese Patent Application Laid-Open No. 0-230526 discloses a phenol resin foam molding that imparts a design property to a foam surface by foaming in a silicone rubber mold capable of transferring complicated shapes and patterns, and that does not require complexing with a skin material. The body was specifically disclosed.

[0008]

However, the phenolic resin foam has a characteristic that gas bubbles at the time of foaming and air bubbles mixed at the time of stirring and mixing hardly come off due to the high viscosity of the raw material. is there. The air bubbles remain after the foam is formed, and the air bubbles generated on the surface of the formed body become pinhole-shaped defects. In particular, it has been found that when the phenolic resin foam according to the present invention has a complicated uneven shape as in the phenolic resin foam, a large number of such bubbles are likely to be generated partially, and when the shape is severe, defects such as depressions are found. The above pinhole-shaped defects are not a major problem when a skin material is attached to a phenol resin foam, but the phenol resin foam molded body used without attaching the skin material impairs the design and appearance. It can be a fatal defect.

In view of the above problems, the present inventor has an object to provide a foamed phenolic resin molded article having a skin layer, which does not have a defective appearance due to air bubbles and does not require complexing with a skin material.

[0010]

That is, according to the first aspect of the present invention, in a method for producing a foamed phenolic resin molded article having a skin layer, at least a synthetic resin is used as the skin layer.
After applying the curable resin composition containing a curing agent to a molding die, a foam-curing phenol resin compounded liquid containing at least a phenol resin, a curing agent, and a foaming agent is injected and foamed in the molding die. By applying the curable resin composition into a mold to form a skin layer before injecting the foam-curable phenol resin compounding liquid, poor appearance due to foam bubbles is prevented and coating with a skin material is unnecessary.

According to a second aspect of the present invention, there is provided the method for producing a foamed phenolic resin molded article having a skin layer according to the first aspect, wherein the injection of the foaming-curable phenolic resin compounding liquid is performed.
At least the inner surface of the skin layer is in an uncured state,
The adhesion between the foam layer and the skin layer becomes good.

According to a third aspect of the present invention, in the method for producing a foamed phenolic resin article having a skin layer according to the first or second aspect, the skin layer is excellent in heat resistance and flame retardancy among synthetic resins. By using a phenolic resin, it is possible to use the molded body at high temperatures, and it has high disaster prevention properties. Good adhesiveness.

According to a fourth aspect of the present invention, in the method for producing a phenolic resin foam molded article having a skin layer according to the first, second, or third aspect, the molding die is a retainer mold having a silicone rubber mold inside. By performing the foaming molding in the silicone rubber mold, it is possible to transfer a design such as a complicated shape or minute unevenness which is difficult with a conventional mold.

[0014] The invention described in claim 5 of the present application is based on claim 1,
2. The method for producing a foamed phenolic resin molded article having a skin layer according to 2, 3, or 4, wherein an antifoaming agent is added to the curable resin composition to suppress the generation of air bubbles at the time of stirring or to reduce the generated air bubbles. Has defoaming effect.

The invention described in claim 6 of the present application is directed to claim 1,
In the method for producing a phenolic resin foam molded article with a skin layer according to 2, 3, 4 or 5, the air bubbles generated at the time of stirring can be removed by performing a vacuum defoaming treatment before applying the curable resin composition. It is possible.

The invention according to claim 7 of the present application is directed to claim 1,
2. The method for producing a foamed phenolic resin article with a skin layer according to 2, 3, 4, 5, or 6, wherein at least two stages of heat treatment are performed after foam molding in the molding die, and the first stage heat treatment is performed at the second stage. By setting the temperature to be lower than the heat treatment, it is possible to provide a strong foamed phenolic resin molded article which does not undergo deformation due to aging and temperature changes.

[0017]

FIG. 1 is a sectional view of a mold used in a method for producing a phenolic resin foam according to the present invention, and FIG. 2 is a phenolic resin foam according to the present invention. However,
These are one embodiment and are not limited thereto. The mold 1 comprises two mold members 2a and 2b that can be opened and closed, an injection port (not shown) for a phenolic resin compounding liquid, and a space 4, and the space 4 can accommodate the silicone rubber mold 3. The mold 1 is a retainer mold made of a metal such as aluminum or a resin, and the shape, pattern, and the like of an article serving as a model of a molded body are transferred to a silicone rubber mold 3 included therein. .

The silicone rubber mold 3 is in a cylindrical state having a handle-shaped cutout portion 5 which is divided into two along a dividing line in a longitudinal direction in order to take out a molded product. The silicone rubber mold 3 has cuts (not shown) penetrating in the thickness direction in order to degas gas and air generated during molding and foaming. If the cut is provided in a biased shape, degassing is easy. In the case where a plurality of cuts are provided, it is desirable that the cuts are provided separately in a portion where air or gas easily accumulates.

The shape and size of the above-mentioned cut are not particularly limited, but in consideration of the life due to breakage of the silicone rubber mold 3 and a diameter of 0.5 to 0.5 mm so as not to substantially damage the surface of the foamed molded product. It is preferable that the silicone rubber mold 3 is penetrated by rotating a thin drill blade of 3 mm. The cuts thus processed are usually closed by the elastic force of the silicone rubber mold 3, and holes are opened by foaming pressure during foam molding. Note that the mold 1 may be provided with a vent hole penetrating to the outside for degassing. However, usually mold 1
A vent hole is not essential because there is a gap between the mold and the silicone rubber mold 3 and the gas can be degassed.

A curable resin composition containing at least a synthetic resin and a curing agent is applied to the inside of the silicone rubber mold 3,
After installing the core material 7 covered with the buffer sheet 8 in the center,
A foam-curable phenolic resin-containing liquid containing at least a phenolic resin, a curing agent, and a foaming agent is injected into the space 4 and subjected to foam molding to obtain a phenolic resin foam molded article.

The method of applying the curable resin composition to the molding die is not particularly limited, and for example, a spray method other than a brush, a spatula and a roller can be used. Further, it may be applied to the entire surface of the molding die, or may be applied locally to a portion where air bubbles are likely to occur. The gas bubbles generated when the foaming-curable phenol resin-containing liquid foams are formed on the skin layer 1.
The thickness of the skin layer 10 is preferably 0.05 to 1 mm so that the skin layer 10 does not reach the surface through zero.

The molding die may be heated before application of the curable resin composition, or heating may be started after application. In the case where heating is started after the application, it is not particularly specified whether heating is started before the injection of the foam-curable phenolic resin-mixed liquid or heating is started after the injection. But,
Here, preferably, at least the inner surface of the skin layer 10 is not completely cured before injecting the foam-curable phenol resin compounding liquid. The inner surface is the surface where the skin layer is in contact with the formulation, and when this surface is completely cured,
When the adhesion between the foam layer 9 and the skin layer 10 is deteriorated, gas components released from the foam layer 9 mainly accumulate at the interface between the skin layer 10 and the foam layer 9. The temperature of the molding die is preferably 30 to 100 ° C., and the foaming condition is preferably an ambient temperature of 30 to 100 ° C. for 2 to 60 minutes.

As shown in FIG. 2, the foamed phenolic resin molded article obtained by the above method has a skin layer 10 composed of a curable resin composition, a foamed layer 9 composed of a phenolic resin foam, and a center layer. Has a core material 7 covered with a buffer sheet 8. When the adhesiveness between the curable resin composition and the phenolic resin foam is poor, an adhesive layer may be provided between the skin layer 10 and the foam layer 9.

The core material 7 is not essential, but when used, it is not limited to one having a straight running property in the longitudinal direction, and may have a curve or a single bend. It is preferable that the foam has a dimensional shape and does not have two or more grooves or steps, for the purpose of reducing the contraction stress in the longitudinal direction of the foam. Usually, when forming into a plate shape, steel plate, aluminum plate, gypsum board, asbestos slate plate, calcium silicate plate, wood plate, plywood, particle board, M
A DF plate or the like is used. When forming into a cylindrical or prismatic shape, it is possible to use rod-like or prismatic iron materials, reinforced concrete materials, aluminum materials, wood, laminated materials, etc., or steel pipes, aluminum pipes, paper pipes, etc. on round pipes or square pipes. it can.

The surface of the core 7 may be surrounded by a buffer sheet 8 in order to alleviate shrinkage stress during foam molding and prevent internal cracks. As the buffer sheet 8, a high-expansion polyolefin sheet, a foamed or non-foamed rubber sheet, or the like is used.
The thickness is preferably about 1 to 2 mm.

The curable resin composition used in the present invention contains at least a synthetic resin and a curing agent. In addition, all that can be used for the curable resin composition can be used. Specifically, inorganic fillers, organic fillers, flame retardants, fibrous base materials,
And formaldehyde scavengers.

Examples of the synthetic resin include a phenol resin, a urethane resin, a melamine resin, a urea resin, and an epoxy resin, and a known curing agent suitable for each resin is added. Among them, it is preferable to use a phenol resin excellent in heat resistance and flame retardancy and a curing agent suitable for it.

A phenol resin is a synthetic resin obtained by reacting a phenol with an aldehyde. Examples of phenols include phenol, o-cresol, m-cresol, p-cresol, p-tert-butylphenol, p-tert-octylphenol, p-nonylphenol, 2,4-xylenol, 2,5-xylenol, 2,6 -Xylenol, 3,4-xylenol,
3,5-xylenol, resorcinol, bisphenol-A, catechol, hydroquinone and the like. Phenolic resins are broadly classified into resol-type phenolic resins and novolak-type phenolic resins according to the reaction conditions such as the ratio of phenols to formaldehyde and the catalyst, but it is preferable to use resol-type phenolic resins. Also, a benzylic ether type phenol resin which is a special resol can be used.

When a phenolic resin is used, the same kind of phenolic resin and curing agent as those used in the foaming-curable phenolic resin compounding liquid may not be used, but the industrial productivity and adhesiveness are reduced. It is preferable that they are the same in consideration of the above.

As a curing agent, an acidic curing agent is used for a resole type phenol resin. Examples of commonly used organic acids include organic acids such as p-toluenesulfonic acid, phenolsulfonic acid, xylenesulfonic acid, and benzenesulfonic acid, and inorganic acids such as sulfuric acid, hydrochloric acid, and phosphoric acid. These acid curing agents can be used alone or in combination of two or more.

[0031] Inorganic fillers can be added. Specifically, clay, calcium carbonate, ammonium borate, potassium borate, zinc powder, zinc phosphate, aluminum phosphate,
Ferrite, magnetite, silicon dioxide, aluminum hydroxide and the like can be mentioned, and these can be used alone or as a mixture of two or more. Among them, addition of aluminum hydroxide is preferable. Aluminum hydroxide, besides the advantage of low cost, is less likely to burn itself and
Since it undergoes dehydration and endothermic reaction at 0 to 550 ° C, it exhibits an excellent flame retardant effect such as suppression of resin ignition or continuous inhibition of combustion. Further, an organic filler such as melamine, dicyandiamide, or gelled powdery synthetic resin may be added.

Further, as a generally used flame retardant,
An organic phosphorus compound may be added. Specifically, trimethyl phosphate, triethyl phosphate, tributyl phosphate, trischloroethyl phosphate, trischloropropyl phosphate, trisdichloropropyl phosphate, tris resyl phosphate, trisixylenyl phosphate, cresyl There are diphenyl phosphate, xylenyl diphenyl phosphate and the like.

A fibrous base material may be added. This functions as a dimensional stabilizer, specifically, glass fiber, carbon fiber, aramid fiber, polyimide fiber, novoloid fiber,
Asbestos, ceramic fibers, metal fibers and the like can be used.

A formaldehyde scavenger may be added. The effect of removing formaldehyde that cannot be completely removed by the heat treatment of the present invention can be expected. The use is not particularly limited, but examples thereof include physical adsorption with silica, activated carbon, and the like, and chemical adsorption with a hydrazide compound, a dihydrazide compound, an azole compound, an azine compound, and the like.

However, in order to obtain the desired aesthetic appearance of the present invention, the addition of a foaming agent to the curable resin composition is strictly prohibited. In addition to the fact that the foaming agent is not added, it is desirable to use the following means in order to generate bubbles in the visible portion of the molded article.

The addition of an antifoaming agent is effective. In order to suppress the generation of bubbles during stirring, it is preferable to add a silicone-based antifoaming agent. The present invention is not particularly limited and known ones can be used.Examples include silicone oils such as polymethylsiloxane, polydimethylsiloxane, and diphenylpolysiloxane, and modified silicone oils such as fluorine-modified silicone and glycol-modified silicone. used. When the defoaming agent is in powder form, it is preferably used in the form of an emulsion dispersed in a hydrocarbon oil such as mineral oil, animal or vegetable oil, or a silicone oil. The above defoaming agents may be used alone or in combination of two or more. Further, a filler such as silica may be added to improve the dispersibility of the defoaming agent. The defoaming agent may be added directly to the curable resin composition before stirring, or may be added by stirring and mixing the resin composition so as to spray on the surface.

After stirring, vacuum degassing is also an effective means to remove the mixed air. However, in order to prevent curing during vacuum defoaming, the addition amount of the curing agent is set to 1
It is preferably 5 to 15 parts by weight based on 00 parts by weight. It is also an effective means to use a stirring blade designed to reduce the generation of air bubbles during stirring.

The foam-curable phenolic resin composition used in the present invention contains at least a phenolic resin, a curing agent, and a foaming agent. As the foam-curable phenolic resin compounding liquid, any liquid that can be used for a phenolic resin foam can be used. Specific examples include the above-mentioned inorganic fillers, organic fillers, flame retardants, fibrous base materials, formaldehyde scavengers and the like.

The phenol resin used is a resol type phenol resin. As the curing agent, those usable for the above-mentioned resole type phenol resin can be added.

As the blowing agent, fluorocarbons such as fluorotrichloromethane and trifluorotrichloroethane were generally used. However, alternatives have recently been studied from the viewpoint of environmental problems such as destruction of the ozone layer. In the present invention, known ones can be used, but it is preferable to use one in consideration of safety and environmental aspects. Specifically, volatile hydrocarbons such as butane, pentane, hexane, gasoline, and naphtha; ketones such as acetone and methyl ethyl ketone; alcohols such as methyl alcohol and ethyl alcohol; and halogenated hydrocarbons such as methylene chloride. Is mentioned. These may be used alone or in combination of two or more.

For uniform foaming, it is preferable to add a foam stabilizer. The foam stabilizer acts on the gas bubble film to stabilize it, and has an effect of forming fine uniform bubbles. Although not particularly specified in the present invention, specific examples include nonionic surfactants and silicone-based surfactants.

The amount of the above-mentioned compound was 10
0.5 to 40 parts by weight of a foaming agent, 1 to 50 parts by weight of a curing agent, 0.1 to 10 parts by weight of a foam stabilizer, and 10 to 200 parts by weight of an inorganic filler, based on 0 part by weight. .

It is preferable to perform a heat treatment after the foam molding. It is possible to obtain a strong phenolic resin foam molded article which does not undergo deformation due to aging and temperature changes. In addition, free formaldehyde can be removed by the above heat treatment. The heat treatment is performed in at least two steps, and the first heat treatment is desirably at a lower temperature than the second heat treatment.
More preferably, the first stage heat treatment is below 90 ° C.,
The heat treatment in the second stage is 90 ° C. or higher, and the optimum temperature is 40 to 70 ° C. in the first stage heat treatment and 100 to 130 ° C. in the second stage heat treatment. The heat treatment time is preferably at least 3 hours, more preferably at least 5 hours.

Further, the foamed phenolic resin molded article according to the present invention can be provided with a surface finishing layer such as by painting according to the purpose of use, and can have flame retardancy and design properties.
Further, the formaldehyde scavenger may be added to a paint or the like. Incidentally, the phenolic resin foam molded article according to the present invention,
Since it has a skin layer, it can be used as an interior material without being composited with a skin material, but it is possible to attach a skin material depending on the intended use.

[0045]

Next, the present invention will be described in more detail with reference to specific examples. <Preparation of curable resin composition> Examples 1, 2, 3 100 parts by weight of a liquid resol type phenol resin solution (manufactured by Dainippon Ink and Chemicals, Inc.) and 50 parts by weight of aluminum hydroxide as an inorganic filler (Showa Denko KK) 20 parts by weight of glass fiber (Mild Fiber manufactured by Central Glass Co., Ltd.) as a dimensional stabilizer, and mixed by stirring. Immediately before coating, 9 parts by weight of a 63% aqueous solution of phenolsulfonic acid were added and mixed vigorously with stirring. Thus, a curable phenol resin composition was obtained. Furthermore, in Examples 1 and 2, vacuum defoaming was performed after stirring and mixing. In Example 1, 1 part by weight of a silicone-based antifoaming agent (manufactured by Dow Corning Toray Silicone Co., Ltd.) was added before stirring.

<Preparation of Foam-Curable Phenol Resin Compound> Examples 1, 2, 3 and Comparative Example 1 100 parts by weight of a liquid resol type phenol resin solution (manufactured by Dainippon Ink and Chemicals, Inc.) were modified as a foam stabilizer. 1 part by weight of silicone oil (manufactured by Dow Corning Toray Silicone Co., Ltd.), 1.5 parts by weight of pentane and 1.5 parts by weight of hexane as foaming agents were added and mixed, and then 50 parts by weight of aluminum hydroxide was further used as an inorganic filler. (Showa Denko: Heidilite) and 20 parts by weight of glass fiber as a dimensional stabilizer (Milled fiber by Central Glass Co., Ltd.) were added and mixed. Immediately before casting, 18 parts by weight of a 63% aqueous phenolsulfonic acid solution ( Daiichi Kogyo Seiyaku Co., Ltd .: Resinol PS
-63) and mixed vigorously with stirring to obtain a foam-curable phenolic resin-mixed liquid.

In a resin mold reinforced with a two-part iron frame, a silicone rubber mold made by drawing a drawn log of a natural cedar having a tip diameter of 120 mm and a length of 3 m as a model is cut open in the longitudinal direction. After setting, the curable phenolic resin composition was applied using a silicone rubber spatula, a laminated material having a diameter of 90 mm and a length of 3.1 m serving as a core material was set at the center of the mold, and the mold was closed.

After the mold was heated to 55 ° C., the upper casting port was opened at an angle of 45 ° C., and the above-mentioned foaming-curable phenolic resin-mixed liquid was quickly poured and left standing for 20 minutes to form a foam. Curing was performed. Thereafter, the molded body was released from the mold, and heat-treated in an oven at 50 ° C. for 5 hours and at 100 ° C. for 5 hours. After sufficiently cooling at room temperature, the number of pinhole defects generated on the surface was measured. Was examined. Table 1 shows the results.

[0049]

[Table 1]

As a result, in Examples 1, 2 and 3 in which the curable resin composition was applied to a mold, the number of pinhole-shaped defects was smaller than in Comparative Example 1, and the curable resin composition was vacuum degassed. In the treated Examples 1 and 2, the number of pinhole-like defects was further reduced, and in Example 1 in which an antifoaming agent was further added, no defects were found. The transfer of the fine grain pattern by the silicone rubber mold was also good, and the appearance was very beautiful.

[0051]

As described above, according to the method for producing a phenolic resin foam having a skin layer according to the present invention, the appearance is not deteriorated due to air bubbles, and the adhesion between the skin layer and the foam layer is strong. It is possible to provide a strong phenol resin foam molded article having good heat resistance and flame retardancy and excellent design properties.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a mold during foam molding in a method for producing a phenolic resin foam according to the present invention.

FIG. 2 is a phenolic resin foam molded article with a skin layer obtained by the production method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Die 3 Silicone rubber mold 4 Space part 7 Core material 8 Buffer sheet 9 Foam layer 10 Skin layer

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) B29K 105: 04 B29K 105: 04 C08L 61:06 C08L 61:06 101: 00 101: 00 F term (reference) 4F074 AA59 BA35 BA37 BA39 BA40 BA42 BA45 BA73 BA74 BA95 BB01 CA23 CC04Z CC07Z CE17 CE27 CE57 CE98 DA19 DA50 DA57 DA58 4F202 AA36 AA37 AB01 AB02 AB03 AD11 AG03 AH48 AJ05 CA01 CB13 CB22 CK11 CK42 4F204 AA36 A48 EB11 A03 EB01 A03 AB01 EB28 EF05 EF27 EK24 EL23

Claims (7)

[Claims] 1. A method for producing a foamed phenolic resin molded article having a skin layer, wherein at least a synthetic resin is used as the skin layer.
After applying a curable resin composition containing a curing agent to a molding die, at least a phenolic resin, a curing agent, and a foamed curable phenolic resin-containing liquid containing a foaming agent were injected and foamed in the molding die. A method for producing a foamed phenolic resin article having a skin layer, characterized by comprising: 2. The method for producing a foamed phenolic resin molded article having a skin layer according to claim 1, wherein at least the inner surface of the skin layer is uncured at the time of injecting the foam-curable phenol resin compounding liquid. 3. The method according to claim 1, wherein the synthetic resin constituting the curable resin composition is a phenol resin. 4. The foamed phenolic resin molded article having a skin layer according to claim 1, wherein the molding die is a retainer die enclosing a silicone rubber die, and the molding and foaming are performed in the silicone rubber die. Production method. 5. The method for producing a foamed phenolic resin molded article with a skin layer according to claim 1, wherein an antifoaming agent is added to the curable resin composition. 6. The method for producing a foamed phenolic resin article with a skin layer according to claim 1, wherein the curable resin composition is subjected to vacuum defoaming treatment before application. 7. At least 2 after foam molding in a molding die.
7. A heat treatment in a first stage, wherein the first heat treatment is lower in temperature than the second heat treatment.
The method for producing a foamed phenolic resin article having a skin layer according to the above.